PROJECT SUMMARY Adolescents with type 1 diabetes (T1D) struggle to meet treatment goals ? only 17% met the target for glycemic control in a recent national study ? and many adolescents experience high levels of diabetes distress related to the daily demands of diabetes care. Yet, previous interventions to improve glycemic control in adolescents with type 1 diabetes have only shown modest to moderate effects, and many have been time- intensive and expensive. Thus, there is a need for novel interventions to improve outcomes in adolescents with T1D. Increasing positive affect, or pleasurable engagement with the environment (e.g., feeling happy, cheerful, proud), has been shown to promote the use of more adaptive coping strategies to manage stress. Thus, the proposed study is based on the premise that, by boosting positive affect in teens with diabetes, we will enhance the use of adaptive coping strategies and reduce diabetes distress, thereby improving glycemic control in adolescents. Through an iterative series of pilot studies, our research team adapted a behavioral intervention using a positive psychology framework that we demonstrated to be feasible and acceptable for adolescents with T1D. This intervention is aimed at inducing positive affect in adolescents (age 13-17) through empirically-validated, tailored exercises in gratitude, self-affirmation, and caregiver affirmations. In our pilot studies, the intervention had promising effects on adolescents' quality of life, diabetes-related stress, and family conflict, all of which are closely linked with diabetes distress. We now plan to evaluate the efficacy of the intervention in a multisite, randomized controlled trial. The aims of this study are to 1) evaluate the effects of a positive psychology intervention for adolescents (age 13-17) and their caregivers on glycemic control; 2) evaluate the effects of the intervention on diabetes distress, coping, and self-care behavior; and 3) explore the differential impact of intervention effects across demographic and treatment variables. We plan to randomize 200 adolescent-caregiver dyads to the Positive Affect + Education intervention (n=100) or the Education only intervention (n=100) from two clinical sites (Vanderbilt University Medical Center and Children's National Medical Center). By employing a positive psychology framework, we propose an innovative approach to treat diabetes distress and improve glycemic outcomes. We believe this novel intervention has the potential to improve outcomes in adolescents with T1D, and the use of automated text messaging to deliver the intervention offers possibilities for wide dissemination.